The present invention relates generally to a running control device for a vehicle. More particularly, the invention relates to a cruise control system for an automotive vehicle which can perceive a condition of coming traffic signal installed on a road, on which the own vehicle travels, and appropriately control a speed of the own vehicle and a distance to a preceding vehicle.
According to advancement of performance of automotive vehicle, it has been more important to provide preventive security by recognizing environmental condition, in which own vehicle travels for detecting a condition where accident tends to occur, to given an alarm to a driver for encouraging taking operation for avoiding danger and preventing accident before occurring by automatically controlling the vehicle in positive manner.
More particularly, an automatic cruise control systems which measures a distance to a preceding vehicle traveling ahead of own vehicle using a laser radar or a millimeter wave radar for cruising with controlling the distance constant, have been commercialized. While such systems are premised on use on the highway, application of such system for traveling on ordinary roads toward the future.
Therefore, as prior arts, systems disclosed in Japanese Patent Application Laid-Open No. 3-201100(1991), Japanese Patent Application Laid-Open No. 3-260899(1991) and Japanese Patent Application Laid-Open No. 11-250399(1999). The conventional system disclosed in Japanese Patent Application Laid-Open No. 3-20110 recognizes condition of a traffic signal by image processing to announce a condition of the traffic signal to the driver when the own vehicle reaches a position of a predetermined distance to the traffic signal, and causes deceleration of the vehicle at red light. On the other hand, the conventional system disclosed in Japanese Patent Application Laid-Open No. 3-260899 has means for detecting color information of the traffic signal to stop operation of distance control when a color of the detected traffic signal is a predetermined color.
On the other hand, the conventional system disclosed in Japanese Patent Application Laid-Open No. 11-250399 receives a distance to an intersection and a condition of the traffic signal from a on-road equipment distanced from the intersection for a predetermined distance, and performs control.
On the other hand, in the conventional system, a condition of the traffic signal is estimated the condition of the traffic signal when the own vehicle passes through the intersection on the basis of the received distance to the intersection and a speed of the own vehicle and makes judgment whether the own vehicle can stop at the intersection at a predetermined deceleration characteristics. Then, when the own vehicle can stop at the intersection at the predetermined deceleration characteristics but cannot pass through the intersection safely, an alarm is given to the driver. On the other hand, when the own vehicle cannot stop at the intersection at the predetermined deceleration characteristics, an alarm is given to the driver even when the own vehicle can pass the intersection safely.
However, in the conventional automatic cruise control system, upon traveling on the ordinary road, various drawbacks are encountered. Namely, since the automatic cruising system measures only distance, if the preceding vehicle passes through the intersection at yellow light or red light, the own vehicle can follow the preceding vehicle despite of the fact that the traffic signal is red light.
On the other hand, since deceleration is taken place only in consideration of the condition of the traffic signal when the own vehicle passes through the intersection, unnecessary deceleration can be caused, and deceleration with taking stoppage of the preceding vehicle into account cannot be performed. Therefore, more delicate vehicle distance control cannot be performed.
The present invention has been worked out in view of the problems set forth above. Therefore, it is an object of the present invention to provide a cruise control system for an automotive vehicle to control speed of own vehicle estimating conditions not only when the own vehicle passes through the intersection but also when the preceding vehicle passes through the intersection, for permitting travel on the ordinary road with a given distance.
In order to accomplish the above-mentioned object, a cruise control system for an automotive vehicle, according to one aspect of the present invention, for controlling cruising of own vehicle with maintaining a distance to a preceding vehicle constant, comprises:
traffic signal characteristics obtaining means for obtaining characteristics of a traffic signal ahead;
road information obtaining means for obtaining intersection information including a distance to an intersection;
intersection arrival time calculating means for calculating arrival timing of the own vehicle and the preceding vehicle on the basis of a distance to the intersection, an own vehicle speed and a preceding vehicle traveling condition;
traffic signal condition estimating means for estimating the condition of the traffic signal on the basis of the traffic signal characteristics and the intersection arriving time; and
control content modifying means for modifying a content of cruise control of the own vehicle depending upon the estimated traffic signal condition.
On the other hand, in the cruise control system for an automotive vehicle may further comprise right and left turn control signal generating means for generating operation pattern of the own vehicle from a state of turn signal or a route information to a destination generated by the road information obtaining means to input to the control content modifying means.
The traffic signal characteristics obtaining means may include traffic signal characteristics measuring means for measuring characteristics of the traffic signal and traffic signal characteristics learning means for learning a traffic signal characteristics measured by the traffic signal characteristics measuring means.
The traffic signal characteristics learning means may learn intersection information from the road information obtaining means with correspondence to the intersection information.
According to another aspect of the present invention, a cruise control system for an automotive vehicle, for controlling cruising of own vehicle with maintaining a distance to a preceding vehicle constant, comprises:
traffic signal characteristics obtaining means including image pick-up means having zooming means, image processing means obtaining a traffic signal characteristics by processing an image of the image pick-up means and communication means, for serving as measuring means for obtaining characteristics of a traffic signal ahead;
road information obtaining means for obtaining intersection information including a distance to an intersection ahead;
intersection arrival time calculating means for calculating arrival timing of the own vehicle and the preceding vehicle on the basis of a distance to the intersection, an own vehicle speed and a preceding vehicle traveling condition;
traffic signal condition estimating means for estimating the condition of the traffic signal on the basis of the traffic signal characteristics and the intersection arriving time;
right and left turn control signal generating means for generating operation pattern of the own vehicle from a state of turn signal or a route information to a destination generated by the road information obtaining means to input to the control content modifying means;
control content modifying means for modifying a content of cruise control of the own vehicle depending upon the estimated traffic signal condition; and
alarm means for generating a corresponding alarm beforehand of modifying the content of control.
On the other hand, the cruise control system for the automotive vehicle has communication means for obtaining the traveling condition of the preceding vehicle from outside. On the basis of the traveling condition (distance and relative speed) of the preceding vehicle obtained via the communication means, the intersection arriving time of the preceding vehicle and the signal condition (red, green or yellow) at arrival timing are estimated to perform vehicle control. Here, the traveling condition of the preceding vehicle from the communication means may be the traveling condition of one or more preceding vehicle.